I would like to know how staad calculate story stiffness?
I am using FLOOR DIAPHRAGM and PRINT STORY STIFFNESS to get story stiffness from staad.
Now suppose structure with 5 floor and same height. All column and beam are of same size. When I check story stiffness result why they differ floor to floor when all floor are similar?
Please find the attached document which explains the process of calculation of storey stiffness in the presence of rigid floor diaphragm.